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From:   Vasily Averin <vvs@virtuozzo.com>
Subject: [PATCH] ext4: remove code duplication in
 update_ind/bind/tind_extent_range
To:     linux-ext4@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>
Cc:     Andreas Dilger <adilger.kernel@dilger.ca>,
        linux-kernel@vger.kernel.org
Message-ID: <1f58b6b3-de16-a08d-2952-5db70dbfc778@virtuozzo.com>
Date:   Sun, 4 Nov 2018 19:41:28 +0300
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Sender: linux-kernel-owner@vger.kernel.org
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update_ind/bind/tind_extent_page() differs by one variable and can be
replaced by unified function. These functions are called by similar way
and their caller function can be simplified too.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
 fs/ext4/migrate.c | 111 ++++++++++------------------------------------
 1 file changed, 23 insertions(+), 88 deletions(-)

diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index 61a9d1927817..02ce99ba32be 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -109,12 +109,13 @@ static int update_extent_range(handle_t *handle, struct inode *inode,
 
 static int update_ind_extent_range(handle_t *handle, struct inode *inode,
 				   ext4_fsblk_t pblock,
-				   struct migrate_struct *lb)
+				   struct migrate_struct *lb,
+				   ext4_lblk_t inc)
 {
 	struct buffer_head *bh;
 	__le32 *i_data;
 	int i, retval = 0;
-	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+	ext4_lblk_t max_entries = inode->i_sb->s_blocksize >> 2;
 
 	bh = sb_bread(inode->i_sb, pblock);
 	if (!bh)
@@ -128,67 +129,7 @@ static int update_ind_extent_range(handle_t *handle, struct inode *inode,
 			if (retval)
 				break;
 		} else {
-			lb->curr_block++;
-		}
-	}
-	put_bh(bh);
-	return retval;
-
-}
-
-static int update_dind_extent_range(handle_t *handle, struct inode *inode,
-				    ext4_fsblk_t pblock,
-				    struct migrate_struct *lb)
-{
-	struct buffer_head *bh;
-	__le32 *i_data;
-	int i, retval = 0;
-	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
-
-	bh = sb_bread(inode->i_sb, pblock);
-	if (!bh)
-		return -EIO;
-
-	i_data = (__le32 *)bh->b_data;
-	for (i = 0; i < max_entries; i++) {
-		if (i_data[i]) {
-			retval = update_ind_extent_range(handle, inode,
-						le32_to_cpu(i_data[i]), lb);
-			if (retval)
-				break;
-		} else {
-			/* Only update the file block number */
-			lb->curr_block += max_entries;
-		}
-	}
-	put_bh(bh);
-	return retval;
-
-}
-
-static int update_tind_extent_range(handle_t *handle, struct inode *inode,
-				    ext4_fsblk_t pblock,
-				    struct migrate_struct *lb)
-{
-	struct buffer_head *bh;
-	__le32 *i_data;
-	int i, retval = 0;
-	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
-
-	bh = sb_bread(inode->i_sb, pblock);
-	if (!bh)
-		return -EIO;
-
-	i_data = (__le32 *)bh->b_data;
-	for (i = 0; i < max_entries; i++) {
-		if (i_data[i]) {
-			retval = update_dind_extent_range(handle, inode,
-						le32_to_cpu(i_data[i]), lb);
-			if (retval)
-				break;
-		} else {
-			/* Only update the file block number */
-			lb->curr_block += max_entries * max_entries;
+			lb->curr_block += inc;
 		}
 	}
 	put_bh(bh);
@@ -433,7 +374,7 @@ int ext4_ext_migrate(struct inode *inode)
 	struct ext4_inode_info *ei;
 	struct inode *tmp_inode = NULL;
 	struct migrate_struct lb;
-	unsigned long max_entries;
+	ext4_lblk_t max_entries, inc, mult;
 	__u32 goal;
 	uid_t owner[2];
 
@@ -523,34 +464,28 @@ int ext4_ext_migrate(struct inode *inode)
 
 	/* 32 bit block address 4 bytes */
 	max_entries = inode->i_sb->s_blocksize >> 2;
-	for (i = 0; i < EXT4_NDIR_BLOCKS; i++) {
+
+	inc = 1; mult = 1;
+	for (i = 0; i < EXT4_N_BLOCKS; i++) {
+		if (i == EXT4_IND_BLOCK)
+			mult = max_entries;
+		else if (i > EXT4_IND_BLOCK)
+			inc = inc * mult;
+
 		if (i_data[i]) {
-			retval = update_extent_range(handle, tmp_inode,
+			if (i < EXT4_IND_BLOCK)
+				retval = update_extent_range(handle, tmp_inode,
 						le32_to_cpu(i_data[i]), &lb);
+			else
+				retval = update_ind_extent_range(handle,
+						tmp_inode,
+						le32_to_cpu(i_data[i]),
+						&lb, inc);
 			if (retval)
 				goto err_out;
-		} else
-			lb.curr_block++;
-	}
-	if (i_data[EXT4_IND_BLOCK]) {
-		retval = update_ind_extent_range(handle, tmp_inode,
-				le32_to_cpu(i_data[EXT4_IND_BLOCK]), &lb);
-			if (retval)
-				goto err_out;
-	} else
-		lb.curr_block += max_entries;
-	if (i_data[EXT4_DIND_BLOCK]) {
-		retval = update_dind_extent_range(handle, tmp_inode,
-				le32_to_cpu(i_data[EXT4_DIND_BLOCK]), &lb);
-			if (retval)
-				goto err_out;
-	} else
-		lb.curr_block += max_entries * max_entries;
-	if (i_data[EXT4_TIND_BLOCK]) {
-		retval = update_tind_extent_range(handle, tmp_inode,
-				le32_to_cpu(i_data[EXT4_TIND_BLOCK]), &lb);
-			if (retval)
-				goto err_out;
+
+		} else if (i < EXT4_TIND_BLOCK)
+			lb.curr_block += inc * mult;
 	}
 	/*
 	 * Build the last extent
-- 
2.17.1